Welding product



0d. 1968 D. P. TANZMAN ET AL 3,404,999

WELDING PRODUCT Filed Oct. 21, 1965 United States Patent 3,404,999 WELDING PRODUCT Daniel P. Tanzman, Far Rockaway, N.Y., and Charles E. Rogers, Kokomo, Ind., assignors to Eutectic Welding Alloys Corporation, New York, N.Y., a corporation of New York Continuation-impart of application 'Ser. No. 419,292, Dec. 18, 1964. This application Oct. 21, 1965, Ser. No. 510,141

14 Claims. (Cl. 117-105) This invention relates to iron base alloy compositions useful for deposition on parent materials. More particularly it relates to self-fluxing iron base alloys for deposition on parent materials, preferably cast iron and steel to produce ductile and machinable deposits. This application is a continuation in part of US. patent application Ser. No. 419,292 filed on Dec. 18, 1964, now abandoned, for Iron Base Alloys.

Alloys which are known to be useful for producing deposits on parent materials have in general been limited to relatively expensive nickel and copper base alloys. This is particularly true where the alloy is to be deposited by the use of a flame spray torch, with or without molten pool generation where the alloy powder is to be self-fluxing. Iron base alloys are in general substantially less expensive than the copper and nickel base alloys but are particularly subject to oxidation during deposition due to their inherent ease of oxidation and their high melting points. Obtaining an easily machinable deposit with the use of iron base alloys has proven diflicult since the known iron base alloys when deposited show inherently poor mechanical properties and are brittle.

It is an object of this invention to provide iron base alloys for use in producing deposits on parent materials. An additional object of this invention is to provide an economical iron base alloy having self-fluxing characteristics. Another object of this invention is to provide such an alloy which produces a ductile, machinable alloy deposit which is porosity free. An iron base alloy which is selffluxing and can be deposited by various welding means such as tungsten inert gas, carbon are or oxyacetlylene heat sources when used in rod form or by metal spraying with or without simultaneous fusion when used in powder form without substantial oxidation is an additional object of this invention. Another object of this invention is to produce such an alloy which has a controlled fluidity during deposition. Other objects of the invention will become apparent as the description proceeds.

The novel features and advantages of the present invention will become apparent to one skilled in the art from a reading of the following description in conjunction with the accompanying drawings wherein similar reference characters refer to similar parts and in which FIG. 1 is a photomicrograph enlarged 500 times of an etched (FeCl etchant) layer of an oxyacetylene flame sprayed deposit of the alloy according to the invention and FIG. 2 is a photomicrograph enlarged 500 times of an unetched layer of an oxyacetylene flame sprayed deposit of the alloy according to the invention.

The iron base alloys of this invention having the aforementioned attributes contain the following constituents in the following percents by weight.

TABLE I Alloys falling in the broad range of Table I exhibit selffluxing properties on steel or cast iron. As such they are not subject to great oxidation during deposition despite the high temperatures used to deposit the alloy. This prop erty makes the alloys particularly useful in the flame spray process. The alloys are of lower price than copper or nickel base alloys having like self fluxing properties. Deposits produced by the iron base alloys of the present invention have outstanding characteristics. The alloys exhibit a deposit hardness ranging from RC 10 to RC 35. The deposits are essentially porosity free.

Excellent machinability is obtained in this alloy due to the presence of flake graphite in the microstructure of the deposit. It is well known that flake graphite in a deposit microstructure imparts machinability by lubricating the tool bit. However, the presence of flake graphite in the deposit formed by the inventive alloy is believed unique for self fluxing alloys. Flake graphite is normally difficult to obtain even under ideal conditions. To obtain flake graphite in a self fluxing iron base alloy under varying conditions of deposit is indeed unexpected.

The existence of flake graphite in the microstructure of the deposits obtained by the use of the iron base alloy of the present invention can be seen by reference to FIGS. 1 and 2.

FIG. 1 is an etched deposit formed by flame spraying the iron base alloy as constiuted in the example of Table I above onto cast iron. The existence of flake graphite 10 in alloy metal deposit 12 can be clearly seen.

FIG. 2 is an unetched deposit of the same alloy flame sprayed on cast iron and also shows flake graphite 10 against metal alloy deposit 12. This figure illustrates that even an unetched deposit shows the existence of the flake graphite.

In addition to the outstanding characteristics of the deposit produced, the iron base alloys of the present invention also have outstanding properties during deposition. During welding of the iron base alloy, the molten pool is sluggish rather than highly fluid. This controlled fluidity allows substantial build up of the molten alloy and deposits of even contour. These properties are particularly useful for example in the overlaying of shafts 3 inches or less in diameter. In such shafts, which have rounded contours, the molten alloy of the present invention is not so fluid as to run off the shaft. This property is also important any time there is a need for a good build up of alloy (e.g. gear teeth). While it is not certain why these properties result it is believed that the interplay of all ingredients making up the alloy extend the temperature between the solidus and liquidus points of the alloy. The resulting wider plastic range allows substantial build up of the molten alloy during deposition. During deposition on parent materials such as cast iron and steel the alloy shows good wetting tendencies.

The alloys of this invention may be prapared as powders in heterogeneous form or a molten homogeneous mixture may be atomized to homogeneous powders. In producing heterogeneous forms iron powder can be added to nickel boron silicon alloys, for example, to achieve the desired chemistry. The self fluxing properties of heterogeneous mechanical mixtures are somewhat inferior to the corresponding homogeneous powders but are adequate to allow deposition by spraying and simultaneous fusion with oxyacetylene spraying equipment. Preferably the homogeneous powder form is utilized.

The alloys may be deposited in numerous methods although the fiame spray method is preferred. Other forms of depositing such as tungsten inert gas welding, carbon arc welding and oxyacetylene welding can be mentioned.

The above described iron base alloys can be utilized in a homogeneous cast rod having the above described alloy constituents.

The above described iron base alloys can be further tilized in homogeneous alloy powder having the above The above described iron base alloy can be deposited a homogeneous alloy weld deposit having the above de- :ribed alloy constituents by combining various hetero- :neous powder forms such as iron powder with various iromium and boron containing constituents which can I 3 produced by mechanically mixing various alloy systems produce the desired powder mixture for simultaneous iraying and molten pool generation on various base letals by use of any heat source such as an oxyacetylene pe welding torch as for example that recited in U.S. atent No. 2,786,779 issued to A. Long et a1. By way of (ample for illustration purposes only, a typical alloy sysm mixture can be produced by mechanically mixing owder forms of the following alloy systems in the weight ercentages indicated in the following examples:

EXAMPLE 1 3 to 55% nickel; ferro-silicon alloy containing 45 to 50% silicon alloy containing 45 to 50% silicon with the balance essentially iron; to of a ferro boron alloy consisting of to 18.5%

boron and the balance essentially iron;

re balance essentially a high carbon iron powder having 5 to 4.3% carbon and the balance essentially iron.

EXAMPLE 2 J to 50% nickel; up to 2% of a ferro silicon allo consisting of 45 to 55% silicon and the balance essentially iron;

to 6% ferro boron alloy conisting of 15 to 18.5% boron and the balance essentially iron;

.e balance of a high carbon iron powder consisting of 5 to 4.3% carbon and the balance essentially iron.

The above decribed iron base alloy could still further deposited as a homogeneous weld deposit having the )ove described alloy constituents in the form of a coated ectrode for electrode arc deposition. The core wire can a of a metal such as for example; mild steel, cast iron, c. It will be understood by those skilled in the art that e metal gore can be flux coated with an alloy containing impatible flux or coating formulation. By way of exnple for illustration purposes only, a typical coated elecode can b as follows:

mild steel core wire coated with the following formula- )n in the indicated weight percentages:

onstituents Weight percent Calcium carbonate 10-21 Lepidolite 10-20 Talc 2-6 Iron oxide .1-5 Ferro boron 17-27 Nickel powder 45-65 Graphite .1-6 Ferro carbide Up to 4 Homogeneous or mechanical mixture powders ofthe loy of the present invention to be utilized for simultanebus spraying and molten pool generation may be advan- "tageously utilized in'particle sizes ranging from below 150 mesh.

The alloys of this invention are particularly useful for the repair welding of cast ironas the deposits form a metallurgical bond withthe" base metal and are machinable. Other typical appliactions include repair of casting defects and machining errors in cast iron.

We claim:

1. An iron base alloy comprising the following constituents in the following percents by weight.

Carbon .1 1-3 Nickel 25-60 Silicon 0-3 Manganese 0-1 Boron 0.5-2 Iron a Balance 3. A method of producing machinable and ductile tieposits on a parent metal comprising spraying and simultaneously fusing the alloy of claim 2 on the parent metal by means of a flame spray torch.

4. The method of claim 3 wherein the parent metal is selected from the group consisting of cast iron and steel.

5. The iron base alloy of claim 1 wherein the alloy is in rod form.

6. A mild steel electrode with an alloy additive bearing coating which when heated to generate a molten pool will deposit an alloy with the ultimate chemistry of said iron base alloy of claim 1.

7. A heterogeneous powder mixture which when heated to generate a molten pool will deposit an alloy with the ultimate chemistry of claim 1.

8. An iron base alloy comprising the following constituents in the following percents by weight.

Carbon 1.75-2.50 Nickel 40-50 Silicon .01-1 Manganese .010.5 Boron 0.75-1.25 Iron Balance 9. The iron base alloy of claim 8 in homogeneous powder form produced by atomizing a homogeneous melt of said alloy.

10. A method of producing machinable and ductile deposits on a parent metal comprising spraying and simultaneously fusing the alloy of claim 9 on the parent metal by means of a flame spray torch.

11. The method of claim 10 wherein the parent metal is selected from the group consisting of cast iron and steel.

12. The iron base alloy of claim 8 wherein the alloy is in rod form. Y

13. A mild steel electrodewith an alloy additive bearing coating which when heated to generate a molten pool will deposit an alloy with the ultimate chemistry of said iron base alloy of claim 8.

14. A heterogeneous powder mixture which when heated to generate a molten pool will deposit an alloy with the ultimate chemistry of claim 8.

No references cited.

RALPH S. KENDALL, Primary Examiner. 

1. AN IRON BASE ALLOY COMPRISING THE FOLLOWING CONSTITUENTS IN THE FOLLOWING PERCENTS BY WEIGHT. CARBON 1-3 NICKEL 25-60 SILICON 0-3 MANGANESE 0-1 BORON 0.5-2 IRON BALANCE 